Air control for fluid fuel burners



Jfine 2Q, 1939. H. c. OLVITT AIR CONTROL FOR FLUID FUEL BURNERS Filed Dec. 26, 1934 M & Q0 0 v R a E QM mm Q R b NM Q1 Q Q -N. mm

Patented June 20, 1939 UNITED STATES PTENT OFFICE Harry G. Olvitt, York, Pa., assignor to York Oil Burner Company, Inc., York, Pa., a corporation of Delaware Application December 26, 1934, Serial No. 759,301

13 Claims.

This invention relates to air controls for oil burners particularly of the type employing means. usually but not necessarily mechanical, for atomizing the fuel oil and for mixing the atomized oil with a stream of air and has for its principal object the provision of means for controlling the volume of air near the exit end of the passageway carrying the air stream rather than at the air intake end of the passageway.

A second object of the invention is to provide an opening at the center and variable openings near the periphery of the air discharge fan whereby the two streams of air coming from said peripheral and central openings may be controlled to a nicety by allowing more or less of the air to pass between the pressure-plate and the forward end of the casing.

A general object of the invention is to improve the air supply means used as a part of oil burning apparatus, and specific objects of the invention pertain to the providing of further means for controlling the division of the air stream and include the provision of a pressure plate which is movable to andfrom the circular casing and g the provision of a damper near the hub of the fan.

In previous oil burners it has been found necessary to carry in stock a great number offans. casings and pressure plates inorderto accommodate the various sizes in which the burners are made and this is objectionable not only because of the first cost of the dies and other equipment but also because of the large amount of stock which it is necessary to keep on hand. By the provisions for control of the air streams in the discharge end I am enabled to make a great number of sizes of oil burners with only a few sizes of casings, fans and pressure plates. My device is in actual operation at the present time in a power unit and I find that I can change a smoky flame into a pure white flame by a rather small variation in my shutter plate which is, the preferred form of control of the air streams and in thus changing the character of the flame I can increase the total hosepower output of the unit by as much as one-third. Furthermore, I find that by providing a'simple means for dividing and controlling the division of the air stream I can readily adjust the burner to the desired flow of fuel, for example, for a desired quantity of oil per unit of time.

In the drawing:

Figure l is a vertical section thru the discharge end of an industrial oil burner.

Figure 2 is an elevation of my pressure plate with its apertured shutters.

Figure 3 is a detail.

The plate H! with its attached snout II is fast to the furnace front and hingedly carries the other parts of the equipment in the usual fashion. The casing is in two parts, a front part l4 and a rear portion [6 of well known construction and housing the centrifugal fan H, the hub l8 of which is secured to the revolving shaft 20 as by the fastening means 2|. The sleeve 23 of the fan just clears the opening in the outside section I6 of the casing, the margin of the opening being denoted" by the numeral 25. Inward of the fan hub l8 and at the end of the shaft 20 is a spinner cup 26 into which the fuel oil is discharged thru the downwardly directed opening in the oil tube 2.! concentric with the shaft 20 but having no engagement therewith. Between the spinner cup 26 and the snout l lis a nose 30 spaced from the spinner cup and the snout and carried by the inner section It of the casing which carries in permanent fashion, as by the screws 32, the pressure plate 35 having the usual conical orifice 36 as an integral portion thereof. The baffle fins 39--may be solid, that is, they may be integral with the pressure plate and have integral enlarged bosses to provide suflicient metal for taking the screws 32 but as illustrated in the drawing I prefer that thesebafile fins, which are used to prevent the air from whirling and forming a vortex, be preferably made in two parts seas to provide for movement of the pressure plate to and from the casing wall while maintaining at all times a baffle extending from the pressure plate rear plane to the casing. This particular feature is shown in detail in Figure 3.

As will be noted, the pressure plate 35, while carried by the casing section [4, is movable with respect to the plate by means of the screws 32 and the-fins 39 are. slotted to receive the follower which rests against a spring diagrammatically indicated as at 4! in the slot 52 of the fin. The movement of thepressure plate to and from the casing will alter the relative volumes of air passing thruithe orifice 36 and thru the nose 30. At the; periphery of the pressure plate I groove the outer or rearward wall and fill this space with an annular shutter 451 having a plurality of rectangular holes 45 therein which may register-with similar holes in the relatively nonmovable portion of the pressure plate or the holes M'may be moved entirely out of registry with the holes 45. The shutter 41 is held against axial movement by the screws t8 but the shutter can revolve to alter the size of th orifices formed bythe openings 44 and 45, a convenient means of extreme simplicity being the small forked handle 51] which engages the shutter 41 to regulate the amount of air which is by-passed between the pressure plate 35 and the casing wall l4. At 5! I have shown an annular damper which is carried by the pressure plate in order to decrease the amount of air that passes thru the conical orifice 36. While I can build a device exactly as illustrated it would be far more usual to use the central damper which may be of either the rose or the iris type or the peripheral shutter 47, or the movable pressure plate but I wish it distinctly to be understood that I am claiming either one of the three or any two of the three or all three of these units, the fundamental idea being to provide a means for dividing the air discharge from the fan into the zone 55 in chosen ratio on opposite sides of the pressure plate, that is, by opening the damper 51 or by closing the shutters, or by moving the pressure plate toward the casing I can increase the relative amount of air passing thru the conical orifice 36 and in opposite fashion I can decrease the amount of air passing thru this conical orifice and increase the amount of air that passes between the nose 3% and the outside wall of the orifice 36. I make no claim to the specific form of the fan as this is of standard type and I have found by experiient that the highest efficiency is had by forming the blades radially instead of at an angle to the diameter.

What I claim is: V

1. In an air control device for an oil burner having an air inlet, a fan casing associated with said air inlet, a fan in said casing for building up pressure within said air casing at the periphery thereof, an air snout, a pressure plate within said fan casing and having a conical orifice located coaxially of said snout, and means for dividing at will the discharge of air from said fan between the inside of the conical orifice and the outside of said conical orifice.

2. In an air control device for oil burners, a circular fan casing having a central air discharge opening, a fan in said casing, a pressure plate within the casing having a central opening through which air from said fan may be discharged and means within the fan casing for altering the relative discharge of air on opposite sides of the plate.

3. In an air control device for oil burners, a circular fan casing having a central air discharge opening, a fan in said casing, a circular plate within the casing, having a central opening thru which air from the fan may be discharged, said plate being axially movable so as to alter the relative discharge of air on opposite sides of the plate and through said openings.

4. In an air control device for oil burners, a fan casing having a central air discharge opening, a fan in said casing, a circular plate having a central opening through which air from the fan may be discharged, a shutter located near the periphery of the plate adapted when closed to cause all the air from the fan to pass through the opening of the plate and when opened to bypass a chosen portion of the air around the plate opening and through the casing opening.

5. In an air control device for oil burners, a fan casing having a central air discharge opening, a fan in said casing, a circular plate having a central opening through which air from the fan may be discharged, a shutter controlling said central opening in the plate and adapted when closed to by-pass the air from the fan around the plate opening and through the casing opening.

6. In an air control device for oil burners, a circular fan casing having an air discharge opening, a pressure plate forming a partition dividing the space within the casing into two chambers, and having a central air discharge opening positioned within and concentric with the casing opening, a fan within one of the chambers adapted to discharge air through either or both of said openings, adjustable means for altering at will the amount of air discharged through the two openings, and a conical nozzle surrounding both of the openings.

7. The device of claim 6 in which the pressure plate carries radial baffles to limit whirling of the air discharged through the casing opening.

8. In an air control device for an oil burner of the spinner cup type, a fan casing having an outlet orifice, a pressure plate within the fan casing and having an air discharge opening coaxial with the casing orifice, baffles between the fan casing and the pressure plate, means for moving the pressure plate with respect to the casing wall, said baffles having spring pressed portions whereby the baffies constantly extend from the pressure plate to the casing wall as the plate is moved.

9. In an oil burner, a fan casing, a fan within the casing, an air discharge cone, a hollow conical spinner cup, located within said cone and .fiaring in the opposite direction thereto, and cooperating with the cone for producing a hollow stream of air of annular cross section and for feeding oil into the inner surface of said stream, a pressure plate within the casing and having a central, annular, curved nozzle for directing a second stream of air into said first mentioned stream at a slight angle thereto but approximately coaxial therewith.

10. The device of claim 9 plus means for controlling the relative volumes of air in said streams by restricting at will the flow of one stream so as to increase the flow of the other stream.

11. The method of obtaining a desired color of flame of oil burning while suspended in an air stream, which consists in dividing air from a single source into a first stream and a second stream, each forming a hollow moving body of air having an annular transverse cross section, discharging fuel oil at a chosen rate into the inner surface of said first oil stream, directing said second coaxial hollow stream of air into the first stream upstream of the point where the oil meets the first stream, said second stream converging slightly inward toward the common axis of the air streams, and in altering the relative amounts of discharge of the two air streams by diverting a portion of one stream into the other stream until the color of the flame becomes substantially white at such chosen rate of feed of the fuel oil.

12. The method of producing a desired color of flame of burning fuel oil which comprises the steps of atomizing the fuel oil, creating a moving body of air, separating at will the body of air into two streams one of which is hollow and surrounds the atomized fuel oil so as to entrain it, confining the second stream of air into hollow conoidal form decreasing rapidly in outer diameter down stream and directing the second stream into the first stream upstream of the point of entrainment of the fuel oil, deflectin the combined streams of air so that their internal diameter increases from the junction of the two air streams to the point of fuel oil entrainment, and adjusting the relative flow of air in the two streams until the color of the flame changes from smoky to substantially clearwhite.

13. In an oil burner, a circular fan casing, an impeller fan within said casing, an air cone discharging air from said casing, a circular pressure plate within the casing, a central conicoid curved nozzle on said plate for discharging air from said fan, a conical oil feeding spinner cup revolving with the impeller fan and located within the cone, the flare of the cup increasing forwardly While the flare of the cone decreases forwardly so that the tapers are opposite thereby producing a hollow stream of air into which the cup discharges oil, said nozzle being coaxial with the cone and cup, the free end of the nozzle surrounding the cup so as to discharge a hollow stream of air into the first mentioned air stream, and means to alter the relative rates of discharge of air on the two sides of the pressure plate and therefore of the rates of discharge of the two hollow air streams, whereby the color of the burner flame may be made substantially white at a chosen rate of oil feed by restricting the flow of air peripherally of the pressure plate with a consequent increase of rate of flow centrally through the pressure plate, or by decreasing the flow through the central nozzle of the pressure plate by decreasing the resistance to peripheral flow about the pressure plate.

HARRY C. OLVITI'. 

